A toll-collect system uses a combination of measures to ensure the correct billing of trucks/cars/motorbikes/vehicles on highways.
A truck driver has different options to pay for highway transit. He can have an onboard unit with GPS and GPRS which automatically senses the truck position and trajectory and sends this information together with truck identification data to a toll-collect server for billing purposes. The other option is a manual registration of the truck at billing stations before entering and/or upon exit of the highway.
All control measures are based on physical evidence, i.e. they detect trucks on highways and check via communication with the toll-collect server if they have paid for the highway section where they are found.
Three control methods exist: automatic billing control; stationary control measures; and mobile control teams.
In automatic billing control, automatic control bridges sense the trucks via a combination of dedicated short-range communications (DSRC) and camera object recognition. The control bridge tries to establish short-range communications to the truck in front of the bridge. If an onboard unit is installed in the truck, it responds and gives the identity of the truck. The control bridge cross-checks with the toll-collect server to determine whether or not there is adequate toll balance for the truck. In case no onboard unit is found, the camera takes pictures of the truck and detects its licence plate. The licence plate is used to check on the toll-collect server if the vehicle has correctly registered for the highway.
In stationary control measures, toll-collect personnel check toll balances manually at parking places.
In addition, mobile teams check trucks while driving on the road.
GPS positioning systems provide an accurate position, but are open to being “spoofed”. For example, in the above toll-collect system, a low-cost transmitter could be fitted to the truck in order to override the authentic GPS signal with a spoof signal arranged to indicate a false location. For example, the false location may be a distribution depot at which the truck is based, or a toll-free road.
The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.